This invention relates to a cutting machine, such as a dicer for dicing a semiconductor wafer.
Japanese Unexamined Patent Publication Nos. 1999-26402 and 1999-74228 each disclose a dicer for cutting a semiconductor wafer along cutting lines arranged in a lattice pattern, i.e., for dicing the semiconductor wafer. In the dicer, a cassette bearing area, a waiting area, a chucking area, a cutting area, and a cleaning area are placed. Cassette supporting means is disposed in the cassette bearing area, temporally supporting means is disposed in the waiting area, and cleaning means is disposed in the cleaning area. The dicer also has a chuck table disposed substantially horizontally movably between the chucking area and the cutting area, cutting means for dicing a workpiece chucked onto the chuck table located in the cutting area, and first transport means, second transport means, and third transport means. On the cassette supporting means, a cassette is borne which accommodates a plurality of workpieces, more detailedly, semiconductor wafers mounted in a central opening of a frame via a mounting tape. The workpiece in the cassette is carried out of the cassette onto the temporally supporting means by the first transport means. Then, the workpiece is transported to the chucking area by the second transport means, and chucked onto the chuck table. The workpiece is moved, together with the chuck table, to the cutting area, where the workpiece is diced by the cutting means. Then, the diced product is moved, together with the chuck table, to the chucking area, whereafter the product is transported from the chuck table to the cleaning area by the third transport means. Then, the product is cleaned by the cleaning means in the cleaning area, and transported from the cleaning area onto the temporally supporting means by the second transport means. Then, the product is carried from the site on the temporally supporting means into the cassette by the first transport means.
The conventional dicer described above poses the problem that the relative arrangement of the cassette bearing area, the waiting area, the chucking area, the cutting area, and the cleaning area is not necessarily rational, so that the entire machine is not fully downsized. To dice a workpiece with high efficiency, it is desired to dispose two cutting means, i.e., the first cutting means and the second cutting means, and make both of the first and second cutting means act on the single workpiece, as disclosed in the aforementioned Japanese Unexamined Patent Publication Nos. 1999-26402 and 1999-74228. However, particularly when the first and second cutting means are disposed, part of the first cutting means and/or the second cutting means locally protrudes, thus making it impossible to make the installation space for the machine sufficiently small. As is well known, the dicer usually needs to be placed in a so-called clean room. In this respect, too, it is strongly desired that the dicer be made as small as possible in size.
A principal object of the present invention is to improve the arrangement of the respective areas in a cutting machine, such as a dicer, to downsize the entire machine sufficiently.
Another object of the invention is to attain the principal object without causing problems such that a workpiece which has been cut and cleaned is recontaminated with swarf.
The inventor of the present invention conducted extensive studies. As a result, the inventor found that the above principal object could be achieved by placing the cassette bearing area, the chucking area, and the cleaning area in this order on a first straight line, which extends in a predetermined direction, in a plan view, and placing the chucking area and the cutting area on a second straight line, which extends substantially perpendicularly to the first straight line, in the plan view.
That is, the invention provides, as a cutting machine for attaining the principal object, a cutting machine comprising cassette supporting means, disposed in a cassette bearing area, for supporting a cassette accommodating a plurality of workpieces; a chuck table disposed substantially horizontally movably between a chucking area and a cutting area; cleaning means disposed in a cleaning area; cutting means for cutting the workpiece chucked on the chuck table located in the cutting area; and workpiece transport means, wherein:
the cassette bearing area, the chucking area, and the cleaning area are placed in this order on a first straight line, which extends in a predetermined direction, in a plan view, while the chucking area and the cutting area are placed on a second straight line, which extends substantially perpendicularly to the first straight line, in the plan view; and
the workpiece accommodated in the cassette is carried out of the cassette to the chucking area by the workpiece transport means, chucked on the chuck table in the chucking area, conveyed to the cutting area together with the chuck table, cut by the cutting means in the cutting area, then returned to the chucking area together with the chuck table, transported from a site on the chuck table to the cleaning means by the workpiece transport means, cleaned by the cleaning means, then transported from the cleaning means to the chucking area by the workpiece transport means, and carried into the cassette by the workpiece transport means.
If desired, temporally supporting means for temporally supporting the workpiece may be disposed in the chucking area so that the workpiece to be cut, which has been carried out of the cassette, can be initially borne on the temporally supporting means, and then transported from a site on the temporally supporting means onto the chuck table, whereafter the workpiece which has been cut and cleaned can be transported from the cleaning means onto the temporally supporting means, and then carried into the cassette. Preferably, the temporally supporting means is composed of a pair of support members placed above the chuck table located in the chucking area, and the pair of support members are movable between an operating position at which the support members are located with a predetermined spacing from each other and the workpiece is borne by the support members in such a manner as to bridge the spacing between the support members, and a non-operating position at which the support members have been moved from the operating position away from each other and the workpiece is allowed to descend through the spacing between the support members.
To attain the other object stated earlier, it is preferred that the workpiece transport means includes first transport means, second transport means, and third transport means; the first transport means carries the workpiece to be cut, out of the cassette onto the temporally supporting means, and carries the workpiece, which has been transported onto the temporally supporting means after being cut and cleaned, from a site on the temporally supporting means into the cassette; the second transport means transports the workpiece to be cut, which has been carried out of the cassette and borne on the temporally supporting means, from a site on the temporally supporting means onto the chuck table, and transports the workpiece, which has been cut and cleaned, from the cleaning means onto the temporally supporting means; and the third transport means transports the workpiece, which has been returned to the chucking area together with the chuck table after being cut, from a site on the chuck table to the cleaning means.
In preferred embodiments, the workpiece comprises a semiconductor wafer, and the cutting means dices the semiconductor wafer. Preferably, the cutting means includes first cutting means and second cutting means; each of the first cutting means and the second cutting means has a rotating shaft, and a cutting blade mounted on the rotating shaft; the rotating shafts are located tandem and extend parallel to the first straight line; and the cutting blades are mounted on ends of the rotating shafts facing each other.